"The income on my Maryland non-resident return is entirely from rental income."
That doesn't matter.
The issue is whether or not the income is taxed by both states. Since the rental income is taxable by both MD and by your resident state, you're entitled to the credit.
The purpose of the "other state credit" is to prevent double taxation.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
